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181.
182.
Golub AS Song BK Pittman RN 《American journal of physiology. Heart and circulatory physiology》2011,301(3):H737-H745
The O(2) disappearance curve (ODC) recorded in an arteriole after the rapid arrest of blood flow reflects the complex interaction among the dissociation of O(2) from hemoglobin, O(2) diffusivity, and rate of respiration in the vascular wall and surrounding tissue. In this study, the analysis of experimental ODCs allowed the estimation of parameters of O(2) transport and O(2) consumption in the microcirculation of the mesentery. We collected ODCs from rapidly arrested blood inside rat mesenteric arterioles using scanning phosphorescence quenching microscopy (PQM). The technique was used to prevent the artifact of accumulated O(2) photoconsumption in stationary media. The observed ODC signatures were close to linear, in contrast to the reported exponential decline of intra-arteriolar Po(2). The rate of Po(2) decrease was 0.43 mmHg/s in 20-μm-diameter arterioles. The duration of the ODC was 290 s, much longer than the 12.8 s reported by other investigators. The arterioles associated with lymphatic microvessels had a higher O(2) disappearance rate of 0.73 mmHg/s. The O(2) flux from arterioles, calculated from the average O(2) disappearance rate, was 0.21 nl O(2)·cm(-2)·s(-1), two orders of magnitude lower than reported in the literature. The physical upper limit of the O(2) consumption rate by the arteriolar wall, calculated from the condition that all O(2) is consumed by the wall, was 452 nl O(2)·cm(-3)·s(-1). From consideration of the microvascular tissue volume fraction in the rat mesentery of 6%, the estimated respiration rate of the vessel wall was ~30 nl O(2)·cm(-3)·s(-1). This result was three orders of magnitude lower than the respiration rate in rat mesenteric arterioles reported by other investigators. Our results demonstrate that O(2) loss from mesenteric arterioles is small and that the O(2) consumption by the arteriolar wall is not unusually large. 相似文献
183.
Countercurrent fermentation is a high performing process design for mixed-acid fermentation. However, there are high operating costs associated with moving solids, which is an integral component of this configuration. This study investigated the effect of volatile solid loading rate (VSLR) and agitation in propagated fixed-bed fermentation, a configuration which may be more commercially viable. To evaluate the role of agitation on fixed-bed configuration performance, continuous mixing was compared with periodic mixing. VSLR was also varied and not found to affect acid yields. However, increased VSLR and liquid retention time did result in higher conversions, productivity, acid concentrations, but lower selectivities. Agitation was demonstrated to be important for this fermentor configuration, the periodically-mixed fermentation had the lowest conversion and yields. Operating at a high pH (~9) contributed to the high selectivity to acetic acid, which might be industrially desirable but at the cost of lower yield compared to a neutral pH. 相似文献
184.
Garai-Ibabe G Grinyte R Golub EI Canaan A de la Chapelle ML Marks RS Pavlov V 《Biosensors & bioelectronics》2011,30(1):272-275
Epstein-Barr virus (EBV) is a human herpes virus that has been associated with several malignancies as Burkitt's lymphoma, nasopharyngeal carcinoma and Hodgkin's disease. All EBV associated malignancies showed a distinct viral gene expression pattern, while Epstein-Barr nuclear antigen 1 (EBNA-1) is constitutively expressed in all such disorders. Here, the development of a biosensor to detect EBNA-1 protein is reported, which was based on a nucleic acid bioreceptor and a quartz crystal microbalance with a dissipation monitoring (QCM-D) transducer. The DNA probe for EBNA-1 detection was designed and synthesized to mimic its palindromic target sites in the EBV genome. This DNA probe was immobilized on the Au-surface of a QCM-D electrode, followed by the blocking of the accessible Au-surface with 6-mercapto-1-hexanol (6-MHO). The system showed a limit of detection of 50 ng/mL in direct detection of EBNA-1, however, the sensitivity was improved by 2 orders of magnitude (0.5 ng/mL) when an amplification cascade, employing antibodies labeled with alkaline phosphatase (AP), was applied to the system. 相似文献
185.
186.
Proteolysis of the cartilage proteoglycan aggrecan is a feature of arthritis. We present a method for analyzing aggrecanolysis in in vitro cultures of 3-week-old mouse femoral head cartilage based on traditional methods developed for large animal species. Investigators can choose either a simple analysis that detects several aggrecan fragments released into culture medium only or a more comprehensive study that detects all fragments present in both the medium and the cartilage matrix. The protocol comprises (i) cartilage culture and optional cartilage extraction, (ii) a quick and simple colorimetric assay for quantitating aggrecan and (iii) neoepitope western blotting to identify specific aggrecan fragments partitioning to the medium or cartilage compartments. The crucial difference between the methods for mice and larger animals is that the proportion of aggrecan in a given sample is normalized to total aggrecan rather than to tissue wet weight. This necessary break from tradition arises because tiny volumes of liquid clinging to mouse cartilage can increase the apparent tissue wet weight, causing unacceptable errors. The protocol has broad application for the in vitro analysis of transgenic mice, particularly those with mutations that affect cartilage remodeling, arthritic disease and skeletal development. The protocol is robust, reliable and takes 7-11 d to complete. 相似文献
187.
188.
AF Nicol JE Golub JR Silva CB Cunha SM Amaro-Filho NS Oliveira W Menezes CV Andrade F Russomano A Tristão B Grinsztejn RK Friedman MP Oliveira A Pires GJ Nuovo 《Memórias do Instituto Oswaldo Cruz》2012,107(5):571-577
Although several studies have evaluated the role of p16INK4a as a diagnostic marker of cervical intraepithelial neoplasia (CIN) and its association with disease progression, studies regarding the role of p16INK4a in human immunodeficiency virus (HIV)-infected patients remain scarce. The present study was designed to determine the potential utility of p16INK4a as a diagnostic marker for CIN and invasive cervical cancer in HIV-positive and negative cervical specimens. An immunohistochemical analysis of p16INK4a was performed in 326 cervical tissue microarray specimens. Performance indicators were calculated and compared using receiving operating characteristics curve (ROC)/area under the curve. In HIV-1-negative women, the percentage of cells that was positive for p16INK4a expression was significantly correlated with the severity of CIN (p < 0.0001). A ROC curve with a cut-off value of 55.28% resulted in a sensitivity of 89%, a specificity of 81%, a positive predictive value of 91% and a negative predictive value of 78%. HIV-seropositive women exhibited decreased expression of p16INK4a in CIN2-3 specimens compared with HIV-negative specimens (p = 0.031). The ROC data underscore the potential utility of p16INK4a under defined conditions as a diagnostic marker for CIN 2-3 staging and invasive cervical cancer. HIV-1 infection, however, is associated with relatively reduced p16INK4a expression in CIN 2-3. 相似文献
189.
190.
In order to form additional innervation sources of the organs, a possibility to preserve the structure of the cranial cervical node transferred on the musculus sterno-mastoideus has been tried. During this manipulation most of neurocytes die. Along the periphery and on the caudal pole of the node a part of cells remain alive. At first the structure and metabolism of these cells is disturbed. However, beginning from the end of the first month after the transfer, the remained cells and the processes formed by them accumulate catecholamines. By the second--third, and especially by the end of the first month after the transfer, the remained cells and the processes sound. A suggestion is made on a possibility to use these neurocytes for creating additional sources of the organs' innervation. 相似文献